Lamp device for vehicle and lighting device for vehicle

ABSTRACT

An adjustment mechanism configured to adjust a reference position of an optical axis of a projection lens of a lens unit has a reference axis perpendicular to the optical axis and disposed in a plane which intersects with a focal point of the projection lens. The lens unit moves in an extension direction of the reference axis in accordance with rotation of a second screw. An acting point of a force to move the lens unit is disposed in a plane formed by the optical axis and the reference axis.

TECHNICAL FIELD

The present invention relates to a lamp and a lighting device to bemounted on a vehicle.

BACKGROUND ART

When a lamp including a projection lens is attached to a housingdefining a lamp chamber, an error might occur in a reference position ofan optical axis of the projection lens with respect to a desiredspecification. There is known a lamp which includes an aiming mechanismin order to eliminate this error.

The aiming mechanism includes two screws exposed to the outside of thehousing. By rotating one of the screws, the reference position in theupper-lower direction of the optical axis of the lamp is adjusted. Byrotating the other of the screws, the reference position in theleft-right direction of the optical axis of the lamp is adjusted (e.g.,see Patent Document 1).

For example, Patent Document 2 discloses a lighting device whichincludes a heat sink for dissipating heat generated due to lightemission of a light source. In the lighting device, the heat sink isdisposed outside of the housing to define a portion of a lamp chamber inwhich the light source is disposed, thereby enhancing the heatdissipation. This lighting device includes a screw for adjusting areference position of an optical axis of an optical system disposedinside the lamp chamber.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: JP-A-2012-43656-   Patent Document 2: JP-A-2011-134637

SUMMARY OF THE INVENTION Problems to be Solved

If a mechanism for adjusting the reference position of the optical axisas disclosed in Patent Document 1 is provided in the lamp, an increasein the number of parts and the occupying space thereof cannot beavoided. Consequently, size-reduction of the lighting device, on whichthe lamp is mounted, is prevented.

Accordingly, a first object of the present invention is to reduce theoccupying space of a lamp including a mechanism for adjusting areference position of an optical axis.

Incidentally, a control circuit for controlling an on/off operation of alight source or an actuator for changing a light distribution state oflight emitted from the light source, or the like, can be a heat source.With higher functionality of a lighting device, the number of heatsource included in a lamp tends to increase. Therefore, it is necessaryto consider the effect of such heat source on the operation state of thelight source. On the other hand, size-reduction has been stronglydemanded for a lamp and a lighting device which are mounted on avehicle.

Accordingly, a second object of the present invention is to suppress theeffect of a heat source provided in a lamp on the operation state of alight source while meeting the demands of size-reduction.

Further, the screw as disclosed in Patent Document 2 extends across theinside and outside of the housing and stress is generated in accordancewith the adjustment operation. Therefore, it is necessary to takecountermeasure for preventing water or dust from entering a lamp chamberthrough a screw installation site. On the other hand, size-reduction hasbeen strongly demanded for a lighting device mounted on a vehicle.

Accordingly, a third object of the present invention is to secure highwater and dust resistance while meeting the demands of size-reduction inthe configuration where a screw for adjusting a reference position of anoptical axis of an optical system disposed in a lamp chamber isprovided.

Means for Solving the Problems

A first aspect of the present invention to achieve the first objectprovides a lamp to be mounted on a vehicle, the lamp comprising:

a light source;

a lens unit including a projection lens which is disposed such that atleast a portion of light emitted from the light source passestherethrough, and a holder which supports the projection lens; and

an adjustment mechanism configured to adjust a reference position of anoptical axis of the projection lens,

wherein the adjustment mechanism includes:

-   -   a reference axis perpendicular to the optical axis and disposed        in a plane which intersects with a focal point of the projection        lens;    -   a first screw configured to adjust the reference position in a        first direction;    -   a second screw configured to adjust the reference position in a        second direction intersecting with the first direction;    -   a first transmission mechanism configured to rotate the lens        unit about the reference axis in accordance with rotation of the        first screw; and    -   a second transmission mechanism configured to move at least a        portion of the lens unit in an extension direction of the        reference axis in accordance with rotation of the second screw,        and

wherein an acting point of a force by the second transmission mechanismto move the optical axis is disposed in a plane formed by the opticalaxis and the reference axis.

According to this configuration, the rotation actions of the first screwand the second screw for adjusting the reference position of the opticalaxis in different intersecting directions can be applied integrally onthe lens unit, and the rotation actions can be converted into themovement relative to a common axis. Especially, the number of parts andthe occupying space of the parts can be reduced as compared to theconfiguration where the rotation action of each screw is applied to amechanism having different axis. Accordingly, it is possible to reducethe occupying space of the lamp including a mechanism for adjusting thereference position of the optical axis.

The lens unit is rotated about the reference axis in accordance with therotation of the first screw and is moved in the extension direction ofthe reference axis in accordance with the rotation of the second screw.Here, the reference axis is perpendicular to the optical axis andlocated on a plane which intersects with the focal point of theprojection lens. Accordingly, a relative position between the focalpoint and the light source is not changed. As a result, the influence ofan operation of adjusting the reference position of the optical axis onthe light distribution by the lamp unit can be suppressed.

An acting point of the second transmission mechanism to the lens unit isdisposed on the plane which is formed by the optical axis and thereference axis. Therefore, a force to move the lens unit in theleft-right direction is applied to the same height as the referenceaxis, and thus, a moment to move the optical axis in the upper-lowerdirection is not generated. In this way, the adjustment accuracy of theoptical axis can be improved while reducing the number of parts and theoccupying space of the parts, as described above.

In the lamp according to the first aspect, the force by the secondtransmission mechanism to move the optical axis may act on the holder.

According to this configuration, since the force to move the opticalaxis is directly applied to the lens unit, the desired displacement isachieved with a smaller force. Accordingly, it is possible to reduce thesize of the second transmission mechanism. As a result, the occupyingspace of the lamp which includes a mechanism for adjusting the referenceposition of the optical axis can be further reduced.

In the lamp according to the first aspect, the projection lens may besupported on the holder to be movable in the extension direction of thereference axis. In this case, the force by the second transmissionmechanism to move the optical axis may act on the projection lens.

According to this configuration, the projection lens can be directlymoved in the extension direction of the reference axis. In this way, itis possible to suppress a moment of tilting the optical axis in thesecond direction even when an acting point of the force to move theoptical axis is spaced apart from the reference axis with respect to thedirection of the optical axis. Accordingly, it is possible to furtherimprove the adjustment accuracy of the optical axis while reducing theoccupying space of the lamp including a mechanism for adjusting thereference position of the optical axis.

In the lamp according to the first aspect, the reference axis may beformed on a portion of the holder.

According to this configuration, it is possible to easily form thereference axis for achieving the displacement of the lens unit asdescribed above by using a process of molding the holder. Accordingly,it is possible to further easily achieve a configuration capable ofreducing the occupying space of the lamp which includes the mechanismfor adjusting the reference position of the optical axis.

In the lamp according to the first aspect, the first direction maycorrespond to an upper-lower direction of the vehicle.

According to this configuration, it is possible to reduce the dimensionin the upper-lower direction, in which restriction on the layout isrelatively high when mounted to the lighting device. Accordingly, it ispossible to improve the effect of reducing the occupying space of thelamp including the mechanism for adjusting the reference position of theoptical axis.

In the lamp according to the first aspect, the first transmissionmechanism may include an actuator having a drive shaft for displacingthe optical axis in the first direction. In this case, the first screwand the drive shaft are arranged along an extension direction thereof.

According to this configuration, the first screw and the drive shaft ofthe actuator can be disposed as close as possible, and the adjustmentfor the reference position of the optical axis of the projection lensand the adjustment for the direction of the optical axis by the actuatorcan be made substantially on the same axis. In this way, it is possibleto reduce the size of the lamp as compared to the configuration wherethese adjustments are made on the different axis. As a result, it ispossible to further reduce the occupying space of the lamp including amechanism for adjusting the reference position of the optical axis.

The lamp according to the first aspect may further comprise a heat sinkwhich supports the light source. In this case, the first screw and thesecond screw may extend through the heat sink.

According to this configuration, it is possible not only to reduce theoccupying space of the lamp including the mechanism for adjusting thereference position of the optical axis, but also to improve the mountingworkability onto the lighting device.

A second aspect of the present invention to achieve the second objectprovides a lamp to be mounted on a vehicle, the lamp comprising:

a first heat sink including a first portion and a second portion whichare at least partially isolated by a gap;

a light source supported on the first portion; and

a control part supported on the second portion and having a circuitwhich is configured to control an on/off operation of the light source.

The heat generated from the circuit of the control part is transmittedto the second portion. However, since the first portion and the secondportion are isolated by the gap, the heat generated from the controlpart is less likely to reach the light source. That is, it is possibleto suppress the effect of the heat source on the operation state of thelight source even while employing the control part having the heatsource in the lamp.

In the lamp according to the second aspect, the control part includes aboard on which the circuit is provided, and a second heat sink which isfixed to the second portion and supports the board.

According to this configuration, the heat generated from the circuit ofthe control part can be more effectively dissipated. Therefore, it ispossible to further suppress the effect of the heat source on theoperation state of the light source even while employing the controlpart having the heat source in the lamp.

In the lamp according to the second aspect, the control part may includea heat transfer member disposed between the board and the second heatsink.

In this case, the heat generated from the circuit provided on the boardcan be more effectively transferred to the second heat sink, and hence,can be dissipated. Therefore, it is possible to further suppress theeffect of the heat source on the operation state of the light sourceeven while employing the control part having the heat source in thelamp.

In the lamp according to the second aspect, the control part may includea board made of conductive material and an insulating material layerformed on the surface of the board. In this case, at least a portion ofthe circuit may be provided on the insulating material layer.

According to this configuration, the board itself can exhibitheat-dissipation function. In this case, it is possible to reduce thenumber of parts of the control part. Therefore, it is possible tosuppress the effect of the heat source on the operation state of thelight source while reducing the size of the control part having the heatsource in the lamp.

In the lamp according to the second aspect, each of the first portionand the second portion may have a portion extending in a first directionof the first heat sink. In this case, a main surface of the board mayextend in a second direction of the first heat sink intersecting withthe first direction of the first heat sink.

According to this configuration, it is possible to suppress the effectof the heat source on the operation state of the light source even whileemploying the control part having the heat source in the lamp. Further,it is possible to provide the lamp having high space utilizationefficiency. For example, it is easy to secure a space for disposing anactuator for changing a light distribution state of light emitted fromthe light source, in the side of the control part. Alternatively, it ispossible to effectively utilize a space occurring in the side of thelamp equipped with such actuator.

In the lamp according to the second aspect, each of the first portionand the second portion may have a portion extending in a front-reardirection. In this case, the light source may be disposed on a firstside of the portion extending in the front-rear direction, and thecontrol part may be disposed on a second side opposite to the first sideof the portion extending in the front-rear direction.

According to this configuration, the heat generated from the controlpart is less likely to reach the light source. Therefore, it is possibleto further suppress the effect of the heat source on the operation stateof the light source even while employing the control part as the heatsource in the lamp. Further, it is possible to provide the lamp havinghigh space utilization efficiency. For example, it is easy to secure aspace for disposing an actuator for changing a light distribution stateof light emitted from the light source on the side of the control part.Alternatively, it is possible to effectively utilize a space occurringin the side of the lamp equipped with such actuator.

A third aspect of the present invention to achieve the second objectprovides a lighting device to be mounted on a vehicle, the lightingdevice comprising:

a housing having a wall formed with an opening and defining at least aportion of a lamp chamber;

a heat sink having a first portion disposed in the lamp chamber and asecond portion exposed to an outside of the housing through the opening;

a light source supported on a first region of the first portion of theheat sink; and

a heat source supported on a second region of the first portion of theheat sink,

wherein the first region is arranged to avoid a shortest path from thesecond region to the second portion.

According to this configuration, it is possible to secure a heatdissipation path such that the heat generated from the heat source doesnot first reach the light source. In this way, the effect of the heatsource disposed inside the lamp chamber on the operation state of thelight source can be suppressed.

As the heat source, an actuator for changing a light distribution stateof light emitted from the light source, a control circuit forcontrolling the actuator, and a control circuit for controlling anon/off operation of the light source, or the like, can be exemplified.

In the lighting device according to the third aspect, heat generatedfrom the heat source may be transferred to the first portion via afixing member which fixes the heat source to the second region.

According to this configuration, it is possible to effectively transferthe heat generated from the heat source by using a member which fixesthe heat source to the heat sink. Therefore, the effect of the heatsource disposed inside the lamp chamber on the operation state of thelight source can be further suppressed.

A fourth aspect of the present invention to achieve the third objectprovides a lighting device to be mounted on a vehicle, the lightingdevice comprising:

a housing having a wall formed with an opening and defining at least aportion of a lamp chamber;

a light source disposed in the lamp chamber;

an optical system configured to guide a light emitted from the lightsource in a predetermined direction;

a heat sink supporting the light source;

at least three fixing portions configured to fix the heat sink to thehousing;

a first screw configured to adjust a reference position of an opticalaxis of the optical system in a first direction; and

a second screw configured to adjust the reference position in a seconddirection intersecting with the first direction,

wherein a first portion of the heat sink faces an inner surface of thewall,

wherein a second portion of the heat sink is exposed to the outside ofthe wall through the opening,

wherein the first screw and the second screw extend through the secondportion of the heat sink,

wherein the at least three fixing portions are disposed at positionsfacing the opening on an outside of the wall, and

wherein the first screw and the second screw are disposed in a regiondefined by straight lines connecting the at least three fixing portionsto each other.

In the above configuration, both the first screw and the second screware disposed in the region defined by the straight lines connecting theat least three fixing portions to each other. In other words, both thefirst screw and the second screw are disposed in the region where afastening force by the fixing members mounted to the fixing portions isstrongly applied in a planar fashion. Accordingly, even when at leastone of the first screw and the second screw is subjected to the rotationoperation by a tool in order to adjust the reference position of theoptical axis of the optical system, the effect of the stress occurringby the operation on the water and dust resistance between the housingand the heat sink can be suppressed.

Further, each fixing portion is disposed at a position facing theopening on the outside of the wall, and the first screw and the secondscrew extend through the second portion of the heat sink. Therefore, itis possible not only to further reduce the occupying space of the lamp,but also to improve the mounting workability onto the lighting device.The reason is that the heat sink is completely assembled to the housingsimply by inserting the second portion through the opening from theinside of the housing.

That is, it is possible to secure a high water and dust resistance whileemploying the configuration that the first screw and the second screwfor adjusting the reference position of the optical axis of the opticalsystem are provided, and meeting the demands of size-reduction.

In the lighting device according to the fourth aspect, a water-resistantmember may be disposed between the first portion of the heat sink andthe inner surface of the wall.

According to this configuration, it is possible to further reliablyprevent moisture or dust from entering the lamp chamber through theopening while meeting the demands of size-reduction.

In the lighting device according to the fourth aspect, an outer surfaceof the wall may include a first thickness portion having a firstthickness and a second thick portion having a second thickness thinnerthan the first thickness. In this case, the at least three fixingportions are a portion of the first thickness portion.

According to this configuration, the stress caused by the rotationoperation of the first screw or the second screw is reliably received bythe first thickness portion. Therefore, it is possible to furthersuppress the effect of the stress on the water and dust resistancebetween the housing and the heat sink while meeting the demands ofsize-reduction.

In the lighting device according to the fourth aspect, the secondportion of the heat sink may have a plurality of grooves extending inthe first direction. In this case, the second thickness portion may bedisposed on extension lines of the plurality of grooves.

The heat dissipated through the heat sink moves along the grooves.According to this configuration, since the first thickness portionhaving a thick thickness is not provided at the heat movementdestination, the dissipation of heat can be smoothly performed withoutbeing hindered. In this way, it is possible to reduce the size of astructure related to the heat dissipation. As a result, it is possibleto meet the demands of additional size-reduction while securing highwater and dust resistance.

In the lighting device according to the fourth aspect, the firstdirection may correspond to an upper-lower direction of the vehicle.

Since the generated heat escapes upward, according to aboveconfiguration, the heat dissipated through the heat sink is effectivelydirected upward along the inside of the grooves. Since the heatdissipation efficiency can be further improved, the size of a structurerelated to the heat dissipation can be reduced. Therefore, it ispossible to meet the demands of additional size-reduction while securinghigh water and dust resistance.

In the lighting device according to the fourth aspect, an insertion pathof a tool for operating at least one of the first screw and the secondscrew may be defined by a boundary surface between the first thicknessportion and the second thickness portion.

According to this configuration, the countermeasure for stress caused bythe operation of the first screw and the second screw and theimprovement in the workability can be both achieved while meeting thedemands of size-reduction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional left side view showing a lightingdevice according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a lamp unit included in thelighting device.

FIG. 3 is a perspective view showing a heat sink and a light sourcewhich are included in the lamp unit.

FIG. 4 is a perspective view showing a portion of the rear surface ofthe lighting device.

FIG. 5 is a perspective view showing a portion of the lamp unit.

FIG. 6 is a perspective view showing a portion of the lamp unit.

FIG. 7 is an exploded perspective view showing an operation control unitincluded in the lamp unit.

FIG. 8 is a perspective view showing the rear surface of the lamp unit.

FIG. 9 is a perspective view showing a lens holder included in the lampunit.

FIGS. 10A to 10C are left side views showing an operation of a firstaiming mechanism included in the lamp unit.

FIGS. 11A to 11C are top views showing an operation of a second aimingmechanism included in the lamp unit.

FIGS. 12A and 12B are left side views showing an operation of a levelingactuator included in the lamp unit.

FIG. 13 is a perspective view showing a portion of the lamp unit.

FIG. 14 is a perspective view showing a lamp unit according to acomparative example.

FIG. 15 is a front view showing the lamp unit according to thecomparative example

FIG. 16 is a partial cross-sectional plan view showing a portion of thelamp unit.

FIG. 17 is a perspective view showing a portion of the rear surface ofthe lighting device.

FIG. 18 is a perspective view showing a portion of the rear surface ofthe lighting device according to the comparative example.

FIGS. 19A and 19B are schematic views showing a portion of the rearsurface of a lighting device according to a modified example.

FIG. 20 is a front view showing a portion of the lighting device.

FIGS. 21A and 21B are views showing a portion of a second aimingmechanism according to the comparative example.

FIGS. 22A and 22B are views showing a portion of the second aimingmechanism.

FIG. 23 is a plan view showing a portion of the lighting device.

FIG. 24 is a cross-sectional view taken along a line XXIV-XXIV shown inFIG. 20.

FIG. 25 is a cross-sectional view taken along a line XXV-XXV shown inFIG. 24.

FIG. 26 is a cross-sectional view showing a portion of a first aimingmechanism according to the comparative example.

FIG. 27 is a perspective view showing a lamp unit according to a firstmodified example.

FIG. 28 is a perspective view showing a lamp unit according to a secondmodified example.

FIG. 29 is a perspective view showing a portion of the lamp unit shownin FIG. 28.

FIG. 30 is a right side view showing a portion of the lamp unit shown inFIG. 28.

FIGS. 31A to 31C are top views showing an operation of a second aimingmechanism included in the lamp unit shown in FIG. 28.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. In each of thedrawings used in the following description, the scale of each member issuitably changed in order to have a recognizable size. Further, the“right” and “left” used in the following description indicate the leftand right directions as seen from a driver's seat.

FIG. 1 is a view showing a cross-section along an upper-lower directionof a portion of a headlamp device 1 (an example of a lighting device) asseen from the left side. The headlamp device 1 is a device to be mountedon a front portion of a vehicle and configured to illuminate the front.The headlamp device 1 includes a housing 2 and a translucent cover 4which is mounted to the housing 2 and partitions and forms a lampchamber 3. A lamp unit 10 (an example of a lamp) is disposed in the lampchamber 3.

FIG. 2 is a perspective view showing an outer appearance of the lampunit 10, as seen from the front right upper side. As shown in FIGS. 1and 2, the lamp unit 10 includes a heat sink 11, a light source unit 12,a lens unit 30, a leveling actuator 15, a light distribution controlunit 16, an operation control unit 17, a first aiming mechanism 18, anda second aiming mechanism 19.

FIG. 3 is a perspective view showing an outer appearance of a portion ofthe heat sink 11 and the light source unit 12 as seen from the frontleft upper side. The heat sink 11 includes a rear plate 11 a extendingin the upper-lower and left-right directions. A support table 11 bextends forward on the front side of the rear plate 11 a. A plurality ofheat dissipation plates 11 c are formed on the rear side of the rearplate 11 a. Each heat dissipation plate 11 c extends in the upper-lowerdirection.

The support table 11 b has a right table 11 b 1 and a left table 11 b 2.A cut-out 11 b 3 extends rearward from a front end of the support table11 b and partitions the right table 11 b 1 and the left table 11 b 2.The right table 11 b 1 is located on the right side of the cut-out 11 b3. The left table 11 b 2 is located on the left side of the cut-out 11 b3. A rear end of the cut-out 11 b 3 is located in front of the rearplate 11 a. A rear end of the right table 11 b 1 is continued to a rearend of the left table 11 b 2. An actuator accommodating portion 11 d isformed below the right table 11 b 1. A control unit accommodatingportion 11 e is formed below the left table 11 b 2.

A right support portion 11 b 4 is provided on a front end portion of theright table 11 b 1. The right support portion 11 b 4 is formed with ahole extending in the front-rear direction. A front end surface of theright support portion 11 b 4 protrudes forward from a front end edge 11b 5 of the right table 11 b 1. Similarly, a left support portion 11 b 6is provided on a front end portion of the left table 11 b 2. The leftsupport portion 11 b 6 is formed with a hole extending in the front-reardirection. A front end surface of the left support portion 11 b 6protrudes forward from a front end edge 11 b 7 of the left table 11 b 2.A lower support portion 11 e 1 is provided on the portion of the controlunit accommodating portion 11 e, which is located below the left supportportion 11 b 6. The lower support portion 11 e 1 is formed with a holeextending in the front-rear direction.

As shown in FIG. 1, the lamp unit 10 is assembled to the housing 2 fromthe inside of the lamp chamber 3. The rear plate 11 a of the heat sink11 faces a rear wall 2 a of the housing 2. As shown in FIG. 4, the rearwall 2 a is formed with an opening 2 b. The portion of the heat sink 11,at which the heat dissipation plates 11 c are formed, is penetrated bythe opening 2 b and is exposed to the outside of the rear wall 2 a.

As shown in FIGS. 1 and 3, the light source unit 12 includes a lightsource 21, an attachment 22 and a reflector 23. As shown in FIG. 3, thelight source 21 is fixed to the support table 11 b of the heat sink 11via the attachment 22. As shown in FIGS. 1 and 2, the reflector 23 isalso fixed to the support table 11 b. A dome-shaped inner surface 23 aof the reflector 23 is a reflecting surface and is disposed to face thelight source 21.

As shown in FIGS. 1 and 2, the lens unit 30 is disposed in front of thereflector 23. The lens unit 30 includes a lens holder 13 and aprojection lens 14. The lens holder 13 has a lens holding portion 13 a.The lens holding portion 13 a is an annular frame and supports theprojection lens 14 on the front surface thereof.

Light emitted from the light source 21 is reflected forward by the innersurface 23 a of the reflector 23, and at least a portion thereof passesthrough the projection lens 14. The light which passes through theprojection lens 14 illuminates the front through the translucent cover4.

As shown in FIG. 1, the leveling actuator 15 includes a case 51, a shaft52 and a joint 53. As shown in FIG. 2, the leveling actuator 15 isdisposed in the actuator accommodating portion 11 d of the heat sink 11such that a tip end of the shaft 52 faces forward. A drive circuit (notshown) provided in the case 51 receives a control signal from theoperation control unit 17. The shaft 52 advances and retreats withrespect to the case 51 in accordance with the control signal. As shownin FIGS. 1 and 2, the joint 53 connects the shaft 52 and a lower endportion 13 b of the lens holder 13.

FIG. 5 is a perspective view showing an outer appearance of the lampunit 10 in the state where the lens holder 13 and the projection lens 14are detached, as seen from the front right upper side. The lightdistribution control unit 16 is fixed to a front end of the supporttable 11 b of the heat sink 11. The light distribution control unit 16includes a movable shade 61, a solenoid 62, a link mechanism 63, and abracket 64.

The movable shade 61 is disposed slightly in front of a rear focal pointof the projection lens 14. Therefore, a portion of the light which isemitted from the light source 21 and reflected by the inner surface 23 aof the reflector 23 is blocked by the movable shade 61. As the shape ofan upper end edge of the movable shade 61 is inverted and projectedforward, a low-beam light distribution pattern is formed in front of avehicle. The low-beam light distribution pattern has a cut-off linecorresponding to the shape of the upper end edge, and a lower portionthereof serves as a lighting area.

A plunger 62 a included in the solenoid 62 is connected to the movableshade 61 via the link mechanism 63. As power is supplied to a coil 62 bincluded in the solenoid 62 and the plunger 62 a is operated, themovable shade 61 is tilted rearward through the link mechanism 63.

In this way, the upper end edge of the movable shade 61 retreatsdownward from an optical axis A (see FIG. 1) of the projection lens 14,so that the blocked state of the light emitted from the light source 21is eliminated. The light, which is emitted from the light source 21 andreflected by the reflector 23, passes through the projection lens 14 toform a high-beam light distribution pattern for illuminating a widerange of the front of a vehicle to a far distance.

The bracket 64 is a plate-like member for supporting the movable shade61, the solenoid 62 and the link mechanism 63. Through-holes arerespectively formed at the positions of the bracket 64, which correspondto the right support portion 11 b 4 and the left support portion 11 b 6of the heat sink 11 shown in FIG. 3. Fixing members 64 a, 64 b such asscrews are fitted into holes respectively formed on the right supportportion 11 b 4 and the left support portion 11 b 6 through respectivethough-holes, so that the light distribution control unit 16 is fixed tothe support table 11 b of the heat sink 11.

FIG. 6 is a perspective view showing an outer appearance of the lampunit 10 in the state where the light distribution control unit 16 andthe joint 53 of the leveling actuator 15 are additionally detached fromthe configuration shown in FIG. 5, as seen from the front left upperside. The operation control unit 17 is disposed in the control unitaccommodating portion 11 e of the heat sink 11.

FIG. 7 is an exploded perspective view showing a configuration of theoperation control unit 17. The operation control unit 17 includes acircuit board 71, a connector 72, a fixing plate 73 and a heat transfersheet 74. The operation control unit 17 is disposed in the control unitaccommodating portion 11 e such that a main surface of the circuit board71 extends in the upper-lower direction.

The circuit board 71 includes a first control circuit 71 a forcontrolling at least an on/off operation of the light source 21 of thelight source unit 12, a second control circuit 71 b for controlling anadvance and retreat operation of the shaft 52 of the leveling actuator15, and a third control circuit 71 c for controlling an operation of thesolenoid 62 of the light distribution control unit 16. The connector 72is fixed on the circuit board 71 and is electrically connected to thesecontrol circuits 71 a, 71 b, 71 c. Further, the connector 72 iselectrically connected to an integrated control part (such as ECU)provided in a vehicle side by a signal line (not shown).

Further, the connector 72 is electrically connected to a connectorportion 22 a included in the attachment 22 shown in FIG. 3 via a signalline (not shown). A conductive bus bar (not shown) is provided insidethe attachment 22. A control signal, which is outputted from the firstcontrol circuit 71 a according to the instructions from the integratedcontrol part, is inputted to the light source 21 via the connector 72,the connector portion 22 a of the attachment 22, and the bus bar. Inthis way, an operation of the light source 21 corresponding to thecontrol signal is implemented.

Further, the connector 72 is electrically connected to a drive circuitprovided in the case 51 of the leveling actuator 15 via a signal line(not shown). A control signal, which is outputted from the secondcontrol circuit 71 b according to the instructions from the integratedcontrol part, is inputted to the drive circuit in the case 51 via theconnector 72. In this way, an operation of the shaft 52 corresponding tothe control signal is implemented.

Further, the connector 72 is electrically connected to a drive circuitprovided in the solenoid 62 of the light distribution control unit 16via a signal line (both the drive circuit and the signal line are notshown). A control signal, which is outputted from the third controlcircuit 71 c according to the instructions from the integrated controlpart, is inputted to the drive circuit of the solenoid 62 via theconnector 72. In this way, an operation of the solenoid 62 correspondingto the control signal is implemented.

The heat transfer sheet 74 is a member made of high-thermal conductivematerial such as silicone or acrylic and transfers heat generated in thecontrol circuit to the fixing plate 73. The heat transfer sheet 74 canbe replaced with heat transfer grease.

The fixing plate 73 is a member made of material which has high thermalconductivity and suitable rigidity, such as aluminum. A fixing piece 73a is provided in the front end portion of the fixing plate 73. Thefixing piece 73 a is formed with a through-hole. As shown in FIG. 6, thefixing piece 73 a is disposed such that the through-hole faces a holeformed in the lower support portion 11 e 1 (see FIG. 3) of the heat sink11. Further, the bracket 64 of the light distribution control unit 16shown in FIG. 5 has a through-hole at a position corresponding to thethrough-hole. A fixing member 64 c such as a screw is fitted into thehole formed in the lower support part 11 e 1 through these through-holessuch that the operation control unit 17 is fixed to the control unitaccommodating portion 11 e. At this time, the heat transfer sheet 74 issandwiched between the circuit board 71 and the fixing plate.

Further, as shown in FIG. 3, a first rib 11 a 1, a second rib 11 a 2 anda third rib 11 a 3 are formed on the front surface of the rear plate 11a in the control unit accommodating portion 11 e of the heat sink 11.The first rib 11 a 1 and the second rib 11 a 2 extend in the upper-lowerdirection. The third rib 11 a 3 extends in the left-right direction onthe lower side of the first rib 11 a 1 and the second rib 11 a 2. Asshown in FIG. 6, the operation control unit 17 is disposed in a regiondefined by the first rib 11 a 1, the second rib 11 a 2 and third rib 11a 3, and a position in the left-right direction and the upper-lowerdirection thereof is restricted. In this way, the position of theoperation control unit 17 is stabilized against the vibration from theoutside.

FIG. 8 is a perspective view showing an outer appearance of the lampunit 10 as seen from the rear left side. An annular gasket 11 fextending along a peripheral edge of the rear plate 11 a is mounted onthe rear surface side of the heat sink 11. As shown in FIG. 1, thehousing 2 has an annular frame wall 2 c protruding forward from an innersurface of the rear wall 2 a. When assembling the lamp unit 10 to thehousing 2, the gasket 11 f is accommodated in the frame wall 2 c andprevents moisture or dust from entering into the lamp chamber 3 throughthe opening 2 b. The gasket 11 f can be replaced with a gel-like sealingmember.

As shown in FIGS. 6 and 8, the first aiming mechanism 18 includes afirst screw 81 and a joint 82. The first screw 81 has a head portion 81a and a shaft portion 81 b. As shown in FIG. 8, the head portion 81 a isdisposed on a rear surface side of the lower right portion of the rearplate 11 a of the heat sink 11. As shown in FIG. 6, the shaft portion 81b penetrates through the rear plate 11 a of the heat sink 11 and extendsforward. A threaded groove is formed on an outer peripheral surface ofthe shaft portion 81 b.

The joint 82 has a coupling portion 82 a and a slider portion 82 b. Aright end portion of the coupling portion 82 a is integrally continuedto a front end portion of the slider portion 82 b. The slider portion 82b has an insertion hole which is formed at its inner peripheral surfacewith a threaded groove. As shown in FIG. 6, the shaft portion 81 b ofthe first screw 81 is inserted through the insertion hole formed in theslider portion 82 b, and threaded grooves thereof are screwed with eachother.

When the head portion 81 a of the first screw 81 is rotationallyoperated by a tool (not shown), the screwed position of the shaftportion 81 b and the joint 82 is changed, and the joint 82 is moved inthe front-rear direction. Since the joint 82 is coupled with the case 51of the leveling actuator 15, the leveling actuator 15 is also moved inthe front-rear direction in accordance with the rotation of the firstscrew 81.

The second aiming mechanism 19 includes a second screw 91, a joint 92, alink 93, and a fulcrum member 94. The second screw 91 has a head portion91 a and a shaft portion 91 b.

As shown in FIG. 8, the head portion 91 a is disposed on a rear surfaceside of the upper left portion of the rear plate 11 a of the heat sink11. As shown in FIG. 6, the shaft portion 91 b penetrates through therear plate 11 a of the heat sink 11 and extends forward. A threadedgroove is formed on an outer peripheral surface of the shaft portion 91b. The joint 92 includes a pair of clamping pieces in which a threadedgroove is respectively formed on opposite surfaces. The shaft portion 91b of the second screw 91 is clamped from the upper-lower direction bythe pair of clamping pieces, so that the threaded grooves of theclamping pieces are screwed with the threaded groove of the shaftportion 91 b.

As shown in FIGS. 5 and 6, the link 93 has a first portion 93 aextending in the left-right direction, a second portion 93 b extendingin the front-rear direction, and a third portion 93 c extending in theupper-lower direction. A left end portion of the first portion 93 a isconnected to the joint 92. A rear end portion of the second portion 93 bis connected to the fulcrum member 94. The fulcrum member 94 is providedon a front surface of an upper right portion of the rear plate 11 a ofthe heat sink 11. The left end portion of the first portion 93 a isintegrally continued to the rear end portion of the second portion 93 b.A front end portion of the second portion 93 b is integrally continuedto an upper end portion of the third portion 93 c.

As shown in FIG. 5, on the right side of the reflector 23, a right armportion 23 b is formed and a right bearing 31 is mounted thereon. Theright bearing 31 has a pair of clamping pieces 31 a arranged in theupper-lower direction. A fitting groove 31 b extending in the left-rightdirection is formed between the pair of clamping pieces 31 a. As shownin FIG. 6, on the left side of the reflector 23, a left arm portion 23 cis formed and a left bearing 32 is mounted thereon. The left bearing 32has a pair of clamping pieces 32 a arranged in the upper-lowerdirection. A fitting groove 32 b extending in the left-right directionis formed between the pair of clamping pieces 32 a.

FIG. 9 is a perspective view of the lens holder 13 as seen from the rearlower side. The lens holder 13 further has a right arm portion 13 c, aleft arm portion 13 d, a right shaft portion 13 e, a left shaft portion13 f, and a fitting groove 13 g.

The right arm portion 13 c extends rearward from a right portion of thelens holding portion 13 a. The left arm portion 13 d extends rearwardfrom a left portion of the lens holding portion 13 a. The right shaftportion 13 e is provided at a rear end of the right arm portion 13 c.The left shaft portion 13 f is provided at a rear end of the left armportion 13 d. The fitting groove 13 g is formed between the rightportion of the lens holding portion 13 a and the right arm portion 13 c,and extends in the upper-lower direction.

The right shaft portion 13 e and the left shaft portion 13 f have asubstantially spherical shape, respectively. The right shaft portion 13e and the left shaft portion 13 f are disposed such that a referenceaxis B connecting two shaft portions is perpendicular to the opticalaxis A of the projection lens 14 mounted on the lens holding portion 13a and intersects with a rear focal point of the projection lens 14. Inother words, the reference axis B is perpendicular to the optical axis Aand located on a plane which intersects with the rear focal point of theprojection lens 14.

When the lens holder 13 is mounted as shown in FIG. 2, the third portion93 c of the link 93 of the second aiming mechanism 19 is fitted into thefitting groove 13 g. At this time, a tip end portion 93 c 1 (see FIG. 6)of the third portion 93 c is disposed at the same position as the rightshaft portion 13 e of the lens holder 13 in the upper-lower direction,and is abutted against an inner wall of the fitting groove 13 g.

The right shaft portion 13 e of the lens holder 13 is fitted to theright bearing 31. Specifically, the right shaft portion 13 e is fittedinto the fitting groove 31 b and is clamped by the pair of clampingpieces 31 a. In the fitting groove 31 b, the right shaft portion 13 e isallowed to rotate around the axis B shown in FIG. 9 and to move in theleft-right direction.

A front end portion of the joint 53 included in the leveling actuator 15has a pair of clamping pieces 53 a arranged in the upper-lowerdirection. Meanwhile, a rotation shaft 13 b 1 extending in theleft-right direction is formed on the lower end portion 13 b of the lensholder 13. The rotation shaft 13 b 1 is rotatably clamped between theclamping pieces 53 a.

As shown in FIG. 1, the left shaft portion 13 f of the lens holder 13 isfitted to the left bearing 32. Specifically, the left shaft portion 13 fis fitted into the fitting groove 32 b and is clamped by the pair ofclamping pieces 32 a. In the fitting groove 32 b, the left shaft portion13 f is allowed to rotate around the axis B shown in FIG. 9 and to movein the left-right direction.

FIG. 10 is a left side view for explaining the movement of each part ofthe lamp unit 10 in accordance with the rotation of the first screw 81.The operation control unit 17 is not shown. FIG. 10A shows an initialstate.

When the first screw 81 is rotated to the left from the above state, theleveling actuator 15 is pushed forward. Consequently, the lower endportion 13 b of the lens holder 13 is pushed forward via the joint 53.At this time, the right shaft portion 13 e and the left shaft portion 13f are respectively rotated in a clockwise direction (as seen from theleft) in the fitting grooves 31 b, 32 b of the right bearing 31 and theleft bearing 32. Consequently, the rotation shaft 13 b 1 of the lensholder 13 is rotated rearward between the clamping pieces 53 a of thejoint 53. Accordingly, as shown in FIG. 10B, the optical axis A of theprojection lens 14 is tilted upward.

On the other hand, when the first screw 81 is rotated to the right, theleveling actuator 15 is pushed rearward. Consequently, the lower endportion 13 b of the lens holder 13 is pushed rearward via the joint 53.At this time, the right shaft portion 13 e and the left shaft portion 13f are respectively rotated in a counter-clockwise direction (as seenfrom the left) in the fitting grooves 31 b, 32 b of the right bearing 31and the left bearing 32. Consequently, the rotation shaft 13 b 1 of thelens holder 13 is rotated forward between the clamping pieces 53 a ofthe joint 53. Accordingly, as shown in FIG. 10C, the optical axis A ofthe projection lens 14 is tilted downward.

That is, as the head portion 81 a of the first screw 81 is operated, areference position of the leveling actuator 15, i.e., a referenceposition in the upper-lower direction of the optical axis A of theprojection lens 14 is adjusted.

FIG. 11 is a top view for explaining the movement of each part of thelamp unit 10 in accordance with the rotation of the second screw 91. Theoperation control unit 17 is not shown. FIG. 11A shows an initial state.

When the second screw 91 is rotated to the left from the above state,the first portion 93 a of the link 93 is pushed forward via the joint92. Consequently, the link 93 is rotated to the right with the fulcrummember 94 as a rotation axis, and the right arm portion 13 c of the lensholder 13 is pushed to the right via the third portion 93 c. At thistime, the right shaft portion 13 e and the left shaft portion 13 f arerespectively moved to the right in the fitting grooves 31 b, 32 b of theright bearing 31 and the left bearing 32. Accordingly, as shown in FIG.11B, the optical axis A of the projection lens 14 which is a portion ofthe lamp unit 30 is translated to the right.

On the other hand, when the second screw 91 is rotated to the right, thefirst portion 93 a of the link 93 is pushed rearward via the joint 92.Consequently, the link 93 is rotated to the left with the fulcrum member94 as a rotation axis, and the right arm portion 13 c of the lens holder13 is pushed to the left via the third portion 93 c. At this time, theright shaft portion 13 e and the left shaft portion 13 f arerespectively moved to the left in the fitting grooves 31 b, 32 b of theright bearing 31 and the left bearing 32. Accordingly, as shown in FIG.11C, the optical axis A of the projection lens 14 which is a portion ofthe lamp unit 30 is translated to the left.

That is, as the head portion 91 a of the second screw 91 is operated, areference position in the left-right direction of the optical axis A ofthe projection lens 14 is adjusted.

The leveling actuator 15 is a mechanism for changing a direction of theoptical axis A of the projection lens 14 in the upper-lower direction ofthe vehicle depending on the change in the vehicle due to the number ofpassengers and the loading of luggage. FIG. 12A shows a state (the samestate as FIG. 10C) where the optical axis A of the projection lens 14 issomewhat tilted downward by the operation of the first screw 81. FIG.12B shows a state where the leveling actuator 15 is operated from thestate shown in FIG. 12A and thus the shaft 52 is pulled rearward.

As the shaft 52 is pulled, the lower end portion 13 b of the lens holder13 is further pulled rearward via the joint 53. At this time, the rightshaft portion 13 e and the left shaft portion 13 f are further rotatedin the counter-clockwise direction (as seen from the left) in thefitting grooves 31 b, 32 b of the right bearing 31 and the left bearing32, respectively. Consequently, the rotation shaft 13 b 1 is furtherrotated in the counter-clockwise direction (as seen from the left)between the clamping pieces 53 a of the joint 53. Accordingly, theoptical axis A of the projection lens 14 is further tilted downward.

That is, since the shaft 52 of the leveling actuator 15 further advancesand retreats with reference to the position of the optical axis A of theprojection lens 14, which is adjusted by the operation of the firstscrew 81 and the second screw 91, the optical axis A can be moved in theupper-lower direction.

Hereinafter, an additional detailed configuration of the headlamp device1 configured and operated as described above will be described. FIG. 13is a perspective view showing a part of the lamp unit 10, especially, anelement serving as an adjustment mechanism for adjusting the referenceposition of the optical axis A.

The right shaft portion 13 e and the left shaft portion 13 f of the lensholder 13 respectively form a portion of the reference axis B. The rightbearing 31 and the left bearing 32 hold the right shaft portion 13 e andthe left shaft portion 13 f, respectively. The right shaft portion 13 eand the left shaft portion 13 f are disposed such that the referenceaxis B is perpendicular to the optical axis A of the projection lens 14(not shown) and located on a plane which intersects with a rear focalpoint F of the projection lens 14.

The rotation of the first screw 81 is converted into the front-rearmovement of the joint 82 coupled to the case 51 of the leveling actuator15, thereby rotating the lens unit 30 in the front-rear direction viathe joint 53 (an example of a first transmission mechanism).Specifically, the rotation action of the first screw 81 is applied tothe right shaft portion 13 e and the left shaft portion 13 f, which are,in turn, rotated about the reference axis B in the fitting grooves 31 b,32 b of the right bearing 31 and the left bearing 32. In this way, thereference position in the upper-lower direction (an example of a firstdirection) of the optical axis A is adjusted.

The rotation of the second screw 91 is converted into the front-rearmovement of the joint 92, thereby moving the lens unit 30 in theleft-right direction via the third portion 93 c of the link 93 (anexample of a second transmission mechanism). Specifically, the rotationaction of the second screw 91 is applied to the right shaft portion 13 eand the left shaft portion 13 f, which are, in turn, moved in anextension direction of the reference axis B in the fitting grooves 31 b,32 b of the right bearing 31 and the left bearing 32. In this way, thereference position in the left-right direction (an example of a seconddirection) of the optical axis A is adjusted. Accordingly, the tip endportion 93 c 1 of the third portion 93 c inserted into the fittinggroove 13 g formed in the lens holder 13 is an acting point of thesecond aiming mechanism 19 to the right shaft portion 13 e and the leftshaft portion 13 f.

According to such a configuration, the rotation action of the firstscrew 81 and the second screw 91 for adjusting the reference position ofthe optical axis A for different intersecting directions can be appliedintegrally in the lens unit 30 having the common reference axis B.Especially, the number of parts and the occupying space of the parts canbe reduced as compared to the configuration where the rotation action ofeach screw is applied to a mechanism having different axis. Accordingly,it is possible to reduce the occupying space of the lamp unit 10including a mechanism for adjusting the reference position of theoptical axis A.

The right shaft portion 13 e and the left shaft portion 13 f are rotatedabout the reference axis B in accordance with the rotation of the firstscrew 81 and are moved in the extension direction of the reference axisB in accordance with the rotation of the second screw 91. Here, thereference axis B is perpendicular to the optical axis A and located on aplane which intersects with the rear focal point F of the projectionlens 14. Accordingly, a relative position between the rear focal point Fand the light source 21 is not changed. As a result, the influence of anoperation of adjusting the reference position of the optical axis A onthe light distribution by the lamp unit 10 can be suppressed.

The tip end portion 93 c 1 (an example of an acting point of a secondtransmission mechanism) is an acting point to which the rotation actionof the second screw is applied, and is disposed on a plane which isformed by the optical axis A and the reference axis B. Effects of thisconfiguration will be described with reference to a comparative example.

FIGS. 14 and 15 show a lamp unit 110 according to a comparative example.On the rear side of a lens holder 113 corresponding to the lens holder13, a right shaft portion 113 e and a left shaft portion 113 f areprovided and respectively held by bearings 131, 132. A reference axis B1connecting the right shaft portion 113 e and the left shaft portion 113f corresponds to the reference axis B.

A fitting arm 113 g extends rearward at an upper portion of the lensholder 113. The fitting arm 113 g is fitted into a fitting groove formedin a link 193 corresponding to the link 93. The rotation of a screw 191corresponding to the second screw 91 is converted into the front-rearmovement of a joint 192 corresponding to the joint 92, so that the link193 moves the lens holder 13 in the left-right direction. That is, acoupling point of the link 193 and the fitting arm 113 g is an actingpoint P of a transmission mechanism including the screw 191.

Since the acting point P is positioned above the reference axis B1, amoment M1 of moving an optical axis A1 of the projection lens 114 upwardis generated when the lens holder 113 is moved to the right by the link193 (an arrow R). On the contrary, a moment M2 of moving the opticalaxis A1 of the projection lens 114 downward is generated when the lensholder 113 is moved to the left by the link 193 (an arrow L). Thetransmission mechanism including the screw 191 serves to translate theoptical axis A1 in the left-right direction while maintaining theposition in the upper-lower direction of the optical axis A1. However,in reality, the movement in the upper-lower direction of the opticalaxis A1 occurs due to the movement in the left-right direction of thelens holder 13.

As described above, in the present embodiment, the tip end portion 93 c1 of the link 93 is an acting point to which the rotation action of thesecond screw 91 is applied, and is disposed on the plane which is formedby the optical axis A and the reference axis B. Therefore, a force tomove the lens holder 13 in the left-right direction is applied to thesame height as the reference axis B, and thus, a moment to move theoptical axis A in the upper-lower direction does not occur. In this way,the adjustment accuracy of the optical axis A can be improved whilereducing the number of parts and the occupying space of the parts, asdescribed above.

In the present embodiment, a force to move the optical axis A in theleft-right direction is applied to the lens holder 13. According to thisconfiguration, since the force to move the optical axis A is directlyapplied to the lens unit 30, it is possible to obtain desireddisplacement with a smaller force. In this way, it is possible to reducethe size of the second transmission mechanism. As a result, theoccupying space of the lamp unit 10 which includes a mechanism foradjusting the reference position of the optical axis A can be furtherreduced.

The right shaft portion 13 e and the left shaft portion 13 f, which forma portion of the reference axis B, are formed as a portion of the lensholder 13. According to this configuration, it is possible to easilyform the reference axis B for achieving the displacement of the lensunit 30 as described above by using a process of molding the lens holder13. Accordingly, it is possible to further easily achieve aconfiguration capable of reducing the occupying space of the lamp unit10 which includes the mechanism for adjusting the reference position ofthe optical axis A. Contrary to this configuration, a member having theaxis B on the reflector 23 side may be provided, and a member serving asa bearing may be provided on the lens holder 13 side.

The lamp unit 10 includes the leveling actuator 15 which has the shaft52 (an example of a driving shaft) for displacing the optical axis A ofthe projection lens 14 in the upper-lower direction. The first screw 81and the shaft 52 are arranged to be aligned along the extensiondirection thereof. According to this configuration, the shaft portion 81b of the first screw 81 and the shaft 52 of the leveling actuator 15 canbe as close as possible, and the adjustment for the reference positionof the optical axis A of the projection lens 14 and the adjustment forthe direction of the optical axis A by the leveling actuator 15 can bemade substantially on the same axis. In this way, it is possible toreduce the size of the lamp unit 10 as compared to the configurationwhere these adjustments are made on the different axis. As a result, itis possible to further reduce the occupying space of the lamp unit 10including a mechanism for adjusting the reference position of theoptical axis A.

The first screw 81 to rotate the right shaft portion 13 e and the leftshaft portion 13 f is intended to adjust the position in the upper-lowerdirection of the optical axis A, and the second screw 91 to slide theright shaft portion 13 e and the left shaft portion 13 f is intended toadjust the position in the left-right direction of the optical axis A.Contrary to this configuration, the position in the upper-lowerdirection of the optical axis A may be adjusted by the sliding of theright shaft portion 13 e and the left shaft portion 13 f, and theposition in the left-right direction of the optical axis A may beadjusted by the rotating of the right shaft portion 13 e and the leftshaft portion 13 f. However, the configuration of the present embodimentis desirable to reduce the dimension in the upper-lower direction, inwhich restriction on the layout is relatively high when mounted to theheadlamp device 1. Accordingly, it is possible to improve the effect ofreducing the occupying space of the lamp unit 10 including the mechanismfor adjusting the reference position of the optical axis A.

The first screw 81 and the second screw 91 extend through the portion ofthe heat sink 11, at which the heat dissipation plates 11 c are formed.Therefore, it is possible not only to reduce the occupying space of thelamp unit 10 including the mechanism for adjusting the referenceposition of the optical axis A, but also to improve the mountingworkability onto the headlamp device 1. The reason is that the lamp unit10 is completely assembled to the housing 2 simply by inserting theportion where the heat dissipation plates 11 c are formed into theopening 2 b formed in the rear wall 2 a of the housing 2 from the insideof the lamp chamber 3, as shown in FIG. 1.

FIG. 16 shows a positional relationship among the light source 21supported on the heat sink 11, the light distribution control unit 16and the operation control unit 17, in the lamp unit 10 assembled to thehousing 2.

The rear plate 11 a of the heat sink 11 and the portion located on thefront side thereof are disposed inside the lamp chamber 3 defined by thehousing 2 (an example of a first portion of the heat sink). The portionof the heat sink 11, which is located on the rear side of the rear plate11 a and includes the heat dissipation plates 11 c, is exposed to theoutside of the housing 2 through the opening 2 b formed in the rear wall2 a of the housing 2 (an example of a second portion of the heat sink).

The light source 21 is supported by a light source mounting portion 11 b8 (an example of a first region) provided on an upper surface of theright table 11 b 1 of the heat sink 11. The light distribution controlunit 16 is supported by the right support portion 11 b 4 and the leftsupport portion 11 b 6 (an example of a second region) in the front endof the support table 11 b of the heat sink 11.

A straight line C1 shown in FIG. 16 indicates the shortest path from theright support portion 11 b 4 to the portion of the heat sink 11 exposedto the outside. A straight line C2 indicates the shortest path from theleft support portion 11 b 6 to the portion of the heat sink 11 exposedto the outside. The light source mounting portion 11 b 8 is arranged toavoid the paths C1, C2.

The solenoid 62 (an example of an actuator) included in the lightdistribution control unit 16 can be a heat source during the operationof the headlamp device 1. The heat generated from the solenoid 62 istransferred to the right support portion 11 b 4 and the left supportportion 11 b 6 via the bracket 64. Therefore, the bracket 64 can be alsoa heat source. Subsequently, the heat is transferred along the righttable 11 b 1 and the left table 11 b 2 to reach the heat dissipationplates 11 c, and then, is dissipated to the outside of the housing 2.The paths C1, C2 shown above can be said as a path where the heatgenerated from the solenoid 62 is most quickly transferred.

Here, since the light source mounting portion 11 b 8 is arranged toavoid the paths C1, C2, it is possible to secure a heat dissipation pathwhere the heat generated from the solenoid 62 does not first reach thelight source 21. In this way, the effect of the solenoid 62 as a heatsource disposed inside the lamp chamber 3 on the operation state of thelight source 21 can be suppressed.

Further, the heat, which is generated from the solenoid 62 andtransferred to the bracket 64, is transferred to the support table 11 bvia the fixing members 64 a, 64 b which fix the bracket 64 to the rightsupport portion 11 b 4 and the left support portion 11 b 6. Since heattransfer occurs when the members are in contact with each other, the“transfer” used herein means that the heat transfer via the fixingmembers 64 a, 64 b is dominant. The fixing members 64 a, 64 b extend inthe front-rear direction and respectively enter the inside of the righttable 11 b 1 and the left table 11 b 2. Therefore, the fixing members 64a, 64 b can effectively transfer heat as compared to the portion wherethe bracket 64 is simply in contact with the support table 11 b.

Therefore, it is not necessarily required that the front end edge 11 b 5of the right table 11 b 1 and the front end edge 11 b 7 of the lefttable 11 b 2 are positioned on the rear side of respective front endsurfaces of the right support portion 11 b 4 and the left supportportion 11 b 6 to form a gap between the bracket 64, and the front endedge 11 b 5 and the front end edge 11 b 7. However, by adopting aconfiguration that only the respective front end surfaces of the rightsupport portion 11 b 4 and the left support portion 11 b 6 are incontact with the bracket 64, the heat transfer along the paths C1, C2can be more dominant.

As is apparent from FIGS. 5 and 6, the operation control unit 17 issupported by the lower support portion 11 e 1 (an example of a secondregion) of the control unit accommodating portion 11 e of the heat sink11. Since the lower support portion 11 e 1 is disposed below the supporttable 11 b, it is apparent that the light source mounting portion 11 b 8is arranged to avoid the shortest path from the lower support portion 11e 1 to the portion of the heat sink 11 exposed to the outside.

As described above, the first control circuit 71 a, the second controlcircuit 72 b and the third control unit 73 c, which are included in theoperation control unit 17, control the operation of the light source 21,the solenoid 62 (an example of an actuator) and the leveling actuator 15(an example of an actuator), respectively. These control circuits can bea heat source during the operation of the headlamp device 1. The heatgenerated from each control circuit is transferred to the lower supportportion 11 e 1 via the fixing plate 73. Therefore, the fixing plate 73can be also a heat source. Subsequently, the heat is transferred alongthe control unit accommodating portion 11 e to reach the heatdissipation plates 11 c, and then, is dissipated to the outside of thehousing 2. The shortest path from the lower support portion 11 e 1 tothe heat dissipation plates 11 c can be said as a path where the heatgenerated from the control circuits is most quickly transferred.

Here, since the light source mounting portion 11 b 8 is arranged toavoid the path, it is possible to secure a heat dissipation path wherethe heat generated from each control circuit does not first reach thelight source 21. In this way, the effect of each control circuit as aheat source disposed inside the lamp chamber 3 on the operation state ofthe light source 21 can be suppressed.

Further, the heat, which is generated from each control circuit andtransferred to the fixing plate 73, is transferred to the control unitaccommodating portion 11 e via the fixing member 64 c which fixes thefixing plate 73 to the lower support portion 11 e 1. What is meant bythe “transfer” is the same as described above. Since the fixing member64 c extends in the front-rear direction and enters the inside of thecontrol unit accommodating portion 11 e, it is possible to effectivelytransfer heat.

As is apparent from FIGS. 5 and 6, the leveling actuator 15 is supportedby the actuator accommodating portion 11 d (an example of a secondregion) of the heat sink 11 via the joint 82. Since the actuatoraccommodating portion 11 d is disposed below the support table 11 b, itis apparent that the light source mounting portion 11 b 8 is arranged toavoid the shortest path from the actuator accommodating portion 11 d tothe portion of the heat sink 11 exposed to the outside.

The leveling actuator 15 can be a heat source during the operation ofthe headlamp device 1. The heat generated from the leveling actuator 15is transferred along the actuator accommodating portion 11 d to reachthe heat dissipation plates 11 c, and then, is dissipated to the outsideof the housing 2. The shortest path from the actuator accommodatingportion 11 d to the heat dissipation plates 11 c can be said as a pathwhere the heat generated from the leveling actuator 15 is most quicklytransferred.

Here, since the light source mounting portion 11 b 8 is arranged toavoid the path, it is possible to secure a heat dissipation path wherethe heat generated from the leveling actuator 15 does not first reachthe light source 21. In this way, the effect of the leveling actuator 15as a heat source disposed inside the lamp chamber 3 on the operationstate of the light source 21 can be suppressed.

Further, since a portion of the heat sink 11 is disposed inside the lampchamber 3, the occupying space of the heat sink 11 in the outside of thehousing 2 is minimized. Accordingly, it is possible to provide thesize-reduced headlamp device 1. It is possible to effectively dissipatethe heat generated from each heat source disposed inside the lampchamber 3 while adopting this configuration. Therefore, the effect ofthe heat source on the operation state of the light source 21 can besuppressed.

As shown in FIG. 16, the heat sink 11 (as an example of the first heatsink) includes the right table 11 b 1 (as an example of the firstportion of the first heat sink) and the left table 11 b 2 (as an exampleof the second portion of the first heat sink), which are partitioned bythe cut-out 11 b 3 (an example of the gap). The light source 21 issupported on the right table 11 b 1. As is apparent from FIG. 6, theoperation control unit 17 (an example of the control part) is supportedby the control unit accommodating portion 11 e. The control unitaccommodating portion 11 e is molded integrally with the left table 11 b2 and can be regarded as a portion of the left table 11 b 2.

As described above, the operation control unit 17 includes the firstcontrol circuit 71 a for controlling at least an on/off operation of thelight source 21. The first control circuit 71 a can be a heat sourceduring the operation of the lamp unit 10. The heat generated from thefirst control circuit 71 a is transferred to the left table 11 b 2 viathe control unit accommodating portion 11 e.

However, since the right table 11 b 1 and the left table 11 b 2 areisolated by the cut-out 11 b 3, the heat generated from the firstcontrol circuit 71 a is less likely to reach the light source 21. Thatis, it is possible to suppress the effect of the heat source on theoperation state of the light source 21 even while employing theoperation control unit 17 as a heat source in the lamp unit 10.

The operation control unit 17 includes the board 71 and the fixing plate73. The first control circuit 71 a is provided on the board 71. Thefixing plate 73 is fixed to the control unit accommodating portion 11 ewhile supporting the board 71.

Since the fixing plate 73 is made of high-thermal conductive materialsuch as aluminum, the fixing plate itself serves as a heat dissipationplate (an example of the second heat sink). Therefore, it is possible tomore effectively dissipate the heat generated from the first controlcircuit 71 a.

The operation control unit 17 further includes the heat transfer sheet74 disposed between the board 71 and the fixing plate 73.

In this case, the heat generated from the first control circuit 71 aprovided on the board 71 can be more effectively transferred to thefixing plate 73, and hence, can be subjected to dissipation.

The surface of the board 71 formed of conductive material such asaluminum may be subjected to oxidation treatment or an insulatingmaterial layer may be formed on the surface. At least a portion of thefirst control circuit 71 a, the second control circuit 71 b and thethird control circuit 71 c may be provided on the insulating materiallayer.

According to this configuration, the board 71 itself can exhibitheat-dissipation function. In this case, the fixing plate 73 and theheat transfer sheet 74 are not necessary, and thus, it is possible toreduce the number of parts of the operation control unit 17. Meanwhile,it is required to provide the board 71 with a structure corresponding tothe fixing piece 73 a.

The right table 11 b 1 and the left table 11 b 2 respectively have aportion extending in the front-rear direction (an example of the firstdirection of the first heat sink). A main surface of the board 71extends in the upper-lower direction (an example of the second directionof the first heat sink) intersecting with the front-rear direction.

According to this configuration, it is easy to secure a space fordisposing the leveling actuator 15, in the side of the operation controlunit 17. Therefore, it is possible to provide the lamp unit 10 havinghigh space utilization efficiency. Alternatively, it is possible toeffectively utilize a space occurring in the side of the lamp unit 10equipped with the leveling actuator 15.

As described above, the right table 11 b 1 and the left table 11 b 2have a portion extending in the front-rear direction, respectively.Here, the light source 21 is disposed on the upper side (an example ofthe first side) of the portion extending in the front-rear direction,and the operation control unit 17 is disposed on the lower side (theside opposite to the side where the light source 21 is disposed; anexample of the second side) of the portion extending in the front-reardirection.

According to this configuration, the heat generated from the operationcontrol unit 17 is less likely to reach the light source 21.Accordingly, it is possible to suppress the effect of the heat source onthe operation state of the light source 21 even while employing theoperation control unit 17 as a heat source in the lamp unit 10.

Further, it is easy to secure a space for disposing the levelingactuator 15 in the side of the operation control unit 17. Therefore, itis possible to provide the lamp unit 10 having high space utilizationefficiency. In other words, it is possible to effectively utilize aspace occurring in the side of the lamp unit 10 equipped with theleveling actuator 15.

As shown in FIG. 17, a plurality of heat dissipation plates 11 cextending in the upper-lower direction are formed on the rear surface ofthe rear plate 11 a of the heat sink 11. A total of four posts areprovided between the region (an example of the first portion of the heatsink) where the gasket 11 f is mounted and the region (an example of thesecond portion of the heat sink) where the heat dissipation plates 11 care formed. Each post extends rearward from the rear surface of the rearplate 11 a. Each post is formed with a hole extending in the front-reardirection.

As shown in FIG. 17, the opening 2 b of the housing 2 has asubstantially square shape. A total of four reinforcing blocks 2 d areformed at portions corresponding to four corners of the opening 2 b.Each reinforcing block 2 d is formed by making the thickness of the rearwall 2 a of the housing 2 to be thicker than other portions.

A portion of each reinforcing block 2 b forms a fixing portion 2 d 1which extends to overhang the opening 2 b. In other words, each fixingportion 2 d 1 is disposed at a position facing the opening 2 b on theoutside of the rear wall 2 a. Each fixing portion 2 d 1 is formed with athrough-hole 2 d 2.

As the lamp unit 10 is assembled from the inside of the housing 2, eachof four posts formed on the rear surface of the rear plate 11 a of theheat sink 11 is arranged to face the corresponding one of four fixingportions 2 d 1. The hole formed in each post is arranged to face thecorresponding through-hole 2 d 2. As shown in FIG. 4, a fixing membersuch as a screw is fitted into the hole formed in each post through eachthrough-hole 2 d 2, and hence, the heat sink 11 is fixed to the housing2.

In FIG. 17, a straight line connecting the fixing portions 2 d 1(precisely, the centers of the through-holes 2 d 2) to each other isindicated by a reference numeral D. The first screw 81 and the secondscrew 91 are arranged inside a region defined by the straight lines D.Effects obtained by the above configuration will be described withreference to a comparative example.

FIG. 18 is a perspective view of a headlamp device 101 according to acomparative example as seen from the rear surface side. A portion of aheat sink 111 is exposed to the outside of a housing 102 through anopening 102 b formed in a rear wall 102 a of the housing 102. At aportion of a peripheral edge of the opening 102 b, a total of fourfixing portions 102 d 1 which extend to overhang the opening 102 b areformed by a rolling process. Each fixing portion 102 d 1 is formed witha through-hole 102 d 2 through which a fixing member such as a screw isinserted.

In FIG. 18, a straight line connecting the fixing portions 102 d 1(precisely, the centers of the through-holes 102 d 2) to each other isindicated by a reference numeral D1. A first screw 181 corresponding tothe first screw 81 of the above embodiment is arranged inside a regiondefined by the straight lines D1. On the other hand, a second screw 191corresponding to the second screw 91 of the above embodiment is arrangedoutside the region defined by the straight lines D1.

The region defined by the straight lines D1 corresponds to a regionwhere a fastening force by four fixing members is strongly applied in aplanar fashion. Since the second screw 191 is arranged outside theregion defined by the straight lines D1, a fastening force by the fixingmembers, which is applied to the position of the second screw, isrelatively small. On the other hand, in order to adjust the referenceposition of the optical axis of the projection lens, the second screw191 is subjected to a rotation operation by a tool. When stress by therotation operation is applied to the place which the fastening force bythe fixing members is less likely to reach, a gap tends to occur betweenthe housing 102 and the heat sink 111, and thus, there is a possibilitythat the water and dust resistance is degraded.

On the other hand, in the present embodiment, both the first screw 81and the second screw 91 are disposed inside the region defined by thestraight lines D which connects the fixing portions 2 d 1 to each other.In other words, both the first screw 81 and the second screw 91 aredisposed inside the region where the fastening force by the fixingmembers mounted to the fixing portions 2 d 1 is strongly applied in aplanar fashion. Accordingly, even when at least one of the first screw81 and the second screw 91 is subjected to the rotation operation by atool in order to adjust the reference position of the optical axis A ofthe projection lens 14 (an example of the optical system), the effect ofthe stress occurring by the operation on the water and dust resistancebetween the housing 2 and the heat sink 11 can be suppressed.

Further, each fixing portion 2 d 1 is disposed at a position facing theopening 2 b on the outside of the rear wall 2 a, and the first screw 81and the second screw 91 extend through the portion of the heat sink 11,at which the heat dissipation plates 11 c are formed. Therefore, it ispossible not only to further reduce the occupying space of the lamp unit10, but also to improve the mounting workability onto the headlampdevice 1. The reason is that the lamp unit 10 is completely assembled tothe housing 2 simply by inserting the portion where the heat dissipationplates 11 c are formed into the opening 2 b from the inside of thehousing 2, as shown in FIG. 1.

That is, it is possible to secure a high water and dust resistance whileemploying the configuration that the first screw 81 and the second screw91 for adjusting the reference position of the optical axis A of theprojection lens 14 are provided, and meeting the demands ofsize-reduction.

Further, as described with reference to FIG. 8, the gasket 11 f (as anexample of the water-resistant member) mounted to the back surface ofthe rear plate 11 a of the heat sink 11 is accommodated in the framewall 2 c (see FIG. 1) which forms a portion of an inner surface of therear wall 2 a of the housing 2. With this configuration, moisture ordust is further reliably prevented from entering the lamp chamber 2through the opening 2 b.

The reinforcing blocks 2 d (the first thickness portion) with a thickthickness (as an example of the first thickness) are formed on an outersurface of the housing 2. The expression, “thick thickness,” is used inthe meaning to distinguish from the structure whose dimension in thefront-rear direction is locally increased by a rolling process, as inthe fixing portions 102 d 1 according to the comparative example shownin FIG. 18. That is, although a portions of the fixing portion 102 d 1according to the comparative example extends rearward from theperipheral edge of the opening 102 b, the plate pressure is equal to orless than the sites of the rear wall 102 a other than the portion. Thereinforcing block 2 d in the present embodiment has a shape whosethickness dimension is substantially greater than a plate thickness (asan example of the second thickness) of the sites (as an example of thesecond thickness portion) of the rear wall 2 a other than the portion.

According to this configuration, the stress caused by the rotationoperation of the first screw 81 or the second screw 91 is reliablyreceived by the reinforcing blocks 2 d, and hence, the effect of thestress on the water and dust resistance between the housing 2 and theheat sink 11 can be further suppressed.

As shown in FIG. 17, the reinforcing block 2 d is not provided onextension lines of the grooves formed by the heat dissipation plates 11c. In other words, a region 2 e of the rear wall 2 a located on theextension lines of the grooves is formed by a portion thicker than thereinforcing blocks 2 d.

The heat dissipated through the heat sink 11 moves along the grooves.Since the thick reinforcing block 2 d is not provided at the movementdestination, the dissipation of heat can be smoothly performed withoutbeing hindered.

In the present embodiment, the extension direction of the grooves formedby the heat dissipation plates 11 c is the upper-lower direction (as anexample of the first direction).

Since the heat generated escapes upward, the heat dissipated through theheat sink 11 is effectively directed upward along the inside of thegrooves. Therefore, it is possible to further improve the heatdissipation efficiency.

The reinforcing block 2 d provided at the upper right corner of theopening 2 b has inclined surfaces 2 d 3, 2 d 4 (as an example of theinclined surface) extending in a direction inclined with respect to theupper-lower direction and the left-right direction. The inclined surface2 d 3 forms a boundary with a region 2 f thinner than the reinforcingblock 2 d, and defines an insertion path of a tool for operating thefirst screw 81. The tool is movable in the range of the region 2 f. Theinclined surface 2 d 4 forms a boundary with the region 2 e, and definesan insertion path of a tool for operating the first screw 91. The toolis movable in the range of the region 2 e.

According to this configuration, the countermeasure for stress caused bythe operation of the first screw 81 and the second screw 82 and theimprovement in the workability can be both achieved.

In the above embodiment, a total of four fixing portions 2 d 1 areprovided so as to fix the heat sink 11 to the housing 2. However, thenumber of the fixing portions is not limited to four. The number andarrangement of the fixing portions can be properly determined accordingto the specification of the opening 2 b and the heat sink 11, so long asat least three fixing portions capable of defining a region formed bystraight lines connecting the fixing portions to each other areprovided.

For example, as shown in FIG. 19A, a total of five fixing portions 2 d 1may be provided in the trapezoidal opening 2 b. The positions of thefirst screw 81 and the second screw 91 can be also properly determinedaccording to the specification of the lamp unit 10, so long as the firstscrew 81 and the second screw 91 are disposed within a range defined bythe straight lines D connecting the fixing portions 2 d 1 to each other.FIG. 19B shows an example where a total of three fixing portions 2 d 1are provided in the triangular opening 2 b. The first screw 81 and thesecond screw 91 may be partially located outside the region when therotation axes of the first screw 81 and the second screw 91 are arrangedwithin the range defined by the straight lines D connecting the fixingportions 2 d 1 to each other.

FIG. 20 is a front view showing a portion (in the state where the lensholder 13, the projection lens 14, the light distribution control unit16 and the link 93 are removed) of the lamp unit 10 mounted to thehousing 2. In the present embodiment, the second screw 91 is disposedwithin the range defined by the straight lines D connecting the fixingportions 2 d 1 of the housing 2 to each other. As a result, the secondscrew 91 and the reflector 23 are in close proximity within the lampchamber 3.

FIG. 21A is a perspective view showing the joint 192 according to thecomparative example. The joint 192 has a main body 192 a, clampingpieces 192 b, and locking pieces 192 c. The main body 192 a has arectangular cross-section, as seen in a front view. The clamping pieces192 b are disposed at the rear of the main body 192 a and clamp theshaft portion of the second screw from the upper-lower direction. Thelocking pieces 192 c are disposed in front of the main body 192 a andare fitted and locked to a fitting hole 193 a 1 formed at a left endportion of the link 193 according to the comparative example shown inFIG. 21B. As shown in FIG. 21B, the fitting hole 193 a 1 has arectangular cross-section, as seen in a front view, and the lockingpieces 192 have a rectangle-based shape, as seen in a front view. As thelocking pieces 192 c having such a shape are fitted into the fittinghole 193 a 1 having the rectangular cross-section, the rotation of thejoint 192 due to the rotation of the second screw is prevented.

However, the rectangle-based shape of the joint 192 cannot avoid theincrease of the cross-sectional area in the upper-lower and left-rightdirections, and hence, the link 193 for accommodating a portion of thejoint 192 cannot also avoid the increase of the dimension in theupper-lower and left-right directions. Therefore, when the second screw91 is arranged in close proximity with the reflector 23 as describedabove, there is a possibility that the joint 192 or the link 193interferes with the reflector 23. Alternatively, there is a possibilitythat the position or shape of the reflector 23 is limited in order toavoid such interference.

Therefore, the joint 92 according to the present embodiment isconfigured to form a cylinder-based shape, as shown in FIG. 22A. Thejoint 92 has a main body 92 a, clamping pieces 92 b, locking pieces 92c, and protrusions 92 d. The main body 92 a has a circularcross-section, as seen in a front view. The clamping pieces 92 b aredisposed at the rear of the main body 92 a and clamp the shaft portion91 b of the second screw 91 from the upper-lower direction. The lockingpieces 92 c are disposed in front of the main body 92 a, and are fittedand locked to a fitting hole 93 a 1 formed at a left end portion of thelink 93 shown in FIG. 22B. The protrusions 92 d protrude in theleft-right direction from the left and right sides of the main body 92a.

The fitting hole 93 a 1 has a circular cross-section, as seen in a frontview, and grooves 93 a 2 are formed at an inner wall of the left andright sides of the fitting hole 93 a 1. When the locking pieces 92 c arefitted into the fitting hole 93 a 1, the protrusions 92 d are fitted tothe grooves 93 a 2. The rotation of the joint 92 due to the rotation ofthe second screw 91 is prevented by the engagement between theprotrusions 92 d and the grooves 93 a 2.

According to this configuration, the cross-section area in theupper-lower and left-right directions of the joint 92 can be minimized.Further, the dimension in the upper-lower and left-right directions ofthe link 93 for accommodating a portion of the joint 92 can be alsominimized Therefore, when the second screw 91 is arranged in closeproximity with the reflector 23 as described above, the interference ofthe joint 92 or the link 93 to the reflector 23 can be easily avoided.In other words, the degree of freedom in designing the position andshape of the reflector 23 is improved.

As shown in FIG. 20, the right arm portion 23 b and the left arm portion23 c are formed integrally to the left and right portions of thereflector 23, respectively. The right arm portion 23 b has a firstportion 23 b 1 extending in the upper-lower direction. The right bearing31 for holding the right shaft portion 13 e of the lens holder 13 ismounted to the first portion 23 b 1. Further, the left arm portion 23 chas a first portion 23 c 1 extending in the upper-lower direction. Theleft bearing 32 for holding the left shaft portion 13 f of the lensholder 13 is mounted to the first portion 23 c 1.

FIG. 23 is a plan view of a portion of the lamp unit 10 in the stateshown in FIG. 20, as seen from above. The right arm portion 23 b has asecond portion 23 b 2 extending rearward from the first portion 23 b 1.A rear end of the second portion 23 b 2 is fixed to the support table 11b of the heat sink 11 by a fixing member 23 b 3 such as a screw. Thefixed position by the fixing member 23 b 3 is located immediately behindthe right bearing 31. Further, the left arm portion 23 c has a secondportion 23 c 2 extending rearward from the first portion 23 c 1. A rearend of the second portion 23 c 2 is fixed to the support table 11 b ofthe heat sink 11 by a fixing member 23 c 3 such as a screw. The fixedposition by the fixing member 23 c 3 is located immediately behind theleft bearing 32.

The right shaft portion 13 e and the left shaft portion 13 f of the lensholder 13 are fitted to the fitting groove 31 b of the right bearing 31and the fitting groove 32 b of the left bearing 32 from the front,respectively. According to the configuration described above, a pressingforce rearwardly acting on the reflector 23 during the fitting operationis reliably received at the fixed position by the fixing members 23 b 3,23 c 3. Therefore, the occurrence of the backlash and positionaldeviation of the reflector 23 due to the mounting operation of the lensholder 13 is prevented, so that the accuracy and stability of theoptical system can be secured. That is, the light emitted from the lightsource 21 can be accurately directed to the projection lens 14 by thereflector 23.

As shown in FIG. 23, a connection portion 23 b 4 between the right armportion 23 b and the reflector 23 is disposed in front of both a rearend of the second portion 23 b 2 and a rear end portion 23 d of thereflector 23, so that a concave portion 23 b 5 is defined between thesecond portion 23 b 2 and the reflector 23. Further, a connectionportion 23 c 4 between the left arm portion 23 c and the reflector 23 isdisposed in front of both a rear end of the second portion 23 c 2 andthe rear end portion 23 d of the reflector 23, so that a concave portion23 c 5 is defined between the second portion 23 c 2 and the reflector23.

According to this configuration, the reflector 23 can be mounted to thesupport table 11 b from above in the state where the second screw 91 andthe fulcrum member 94 are first mounted to the rear plate 11 a of theheat sink 11. Therefore, the assembling workability is greatly improved.

In other words, the positions of the connection portions 23 b 4, 23 c 4are determined such that the concave portions 23 b 5, 23 c 5 ofdimensions in which the reflector 23 mounted to the heat sink 11 fromabove is prevented from interfering with the second screw 91 and thefulcrum member 94 can be defined. Since the interference of thereflector 23 with the second screw 91 and the fulcrum member 94 duringthe assembling of the reflector 23 can be avoided, the occurrence of thebacklash and positional deviation of the reflector 23 is prevented, andthus, the accuracy and stability of the optical system can be secured.That is, the light emitted from the light source 21 can be accuratelydirected to the projection lens 14 by the reflector 23.

As shown in FIG. 20, the actuator accommodating portion 11 d of the heatsink 11 is formed with a guide rail 11 d 1. As described above, thejoint 82 of the first aiming mechanism 18 has the coupling portion 82 aand the slider portion 82 b. The coupling portion 82 a extends in theleft-right direction and is coupled to the case 51 of the levelingactuator 15. The slider portion 82 b is fitted into the guide rail 11 d1.

FIG. 24 is a cross-sectional view taken along a line XXIV-XXIV shown inFIG. 20. The guide rail 11 d 1 extends in the front-rear direction andthe slider portion 82 b can be slid in the front-rear direction insidethe guide rail 11 d 1. The slide portion 82 b has a main body 82 b 1, afront through-hole 82 b 2, a rear through-hole 82 b 3, an upper holdingpiece 82 b 4, and a lower holding piece 82 b 5.

The front through-hole 82 b 2 extends rearward from a front end surfaceof the main body 82 b 1 and is formed at its inner peripheral surfacewith a threaded groove. An inner diameter of the front through-hole 82 b2 is substantially the same as an outer diameter of the shaft portion 81b of the first screw 81, and the front through-hole 82 b 2 is screwed tothe threaded groove formed at an outer periphery of the shaft portion 81b. The rear through-hole 82 b 3 extends forward from a rear end surfaceof the main body 82 b 1. An inner diameter of the rear through-hole 82 b3 is greater than an outer diameter of the shaft portion 81 b of thefirst screw 81.

The upper holding piece 82 b 4 is formed integrally with an uppersurface of the main body 82 b 1 and has elasticity. The upper holdingpiece 82 b 4 is in contact with an upper wall 11 d 11 of the guide rail11 d 1. The lower holding piece 82 b 5 is formed integrally with a lowersurface of the main body 82 b 1 and has elasticity. The lower holdingpiece 82 b 5 is in contact with a lower wall 11 d 12 of the guide rail11 d 1.

FIG. 25 is a cross-sectional view taken along a line XXV-XXV shown inFIG. 24. An interval between a right wall 11 d 13 and a left wall 11 d14 of the guide rail 11 d 1 expands toward the front. In other words,the right wall 11 d 13 and the left wall 11 d 14 are inclined in theleft-right direction. These walls are inclined surfaces which arenaturally formed by the draft of a mold used for molding the heat sink11.

A width in the left-right direction of the main body 82 b 1 of theslider portion 82 b expands toward the front. More specifically, a rightsurface and a left surface of the main body 82 b 1 are inclined at anangle corresponding to the draft. In this way, the left and rightsurfaces of the slider portion 82 b is substantially in contact with theright wall 11 d 13 and the left wall 11 d 14 of the guide rail 11 d 1without any gap.

Effects obtained by the above configuration will be described withreference to a comparative example. FIG. 26 is a sectional viewcorresponding to FIG. 25, showing a slider portion 182 b of a jointaccording to a comparative example A width in the left-right directionof a main body 182 b 1 included in the slider portion 182 b issubstantially the same as an interval between the right wall 11 d 13 andthe left wall 11 d 14 in the vicinity of the rear end portion of theguide rail 11 d 1. Further, a through-hole 182 b 2 formed with athreaded groove extends forward from the rear end surface of the mainbody 182 b 1.

In the case of such configuration, the main body 182 b 1 is screwed withthe first screw 181 at the rear portion thereof. A moment occurring dueto the rotation operation of the first screw 181 acts as a force fordisplacing the slider portion 182 b in the left-right direction. Thisaction increases toward the front away from the screwing point. On theother hand, an interval between the main body 182 b 1, and the rightwall 11 d 13 and the left wall 11 d 14 of the guide rail 11 d 1 inclinedby the draft expands toward the front. In this way, a front end portionof the slider portion 182 b is greatly displaced in the left-rightdirection with the rotation of the first screw 181. Since thedisplacement of the slider portion 182 b is transmitted to the shaft 52of the leveling actuator 15 through a coupling portion (not shown)integrally formed, there is a possibility that the precise adjustment ofthe reference position of the optical axis A can be hindered.

On the other hand, in the slider portion 82 b according to the presentembodiment, the main body 82 b 1 is screwed with the first screw 81 atthe front portion thereof. Further, the front portion of the main body82 b 1 is wider than the rear portion thereof, and is in contact withthe right wall 11 d 13 and the left wall 11 d 14 of the guide rail 11 d1 without any gap. Therefore, the moment occurring due to the rotationoperation of the first screw 81 is reliably absorbed, and thedisplacement in the left-right direction of the slider portion 82 b isprevented.

As shown in FIG. 24, an interval between the upper wall 11 d 11 and thelower wall 11 d 12 of the guide rail 11 d 1 also expands toward thefront by the draft. The moment occurring due to the rotation operationof the first screw 81 acts as a force for displacing the slider portion82 b in the upper-lower direction. However, this force is absorbed byelasticity of the upper holding piece 82 b 4 and the lower holding piece82 b 5. Therefore, the displacement in the upper-lower direction of theslider portion 82 b is also prevented.

Since the backlash of the slider portion 82 b within the guide rail 11 d1 is prevented, the rotation action of the first screw 81 is accuratelyand reliably transmitted to the leveling actuator 15. In this way, theadjustment of the reference position of the optical axis A can beaccurately and reliably performed.

The above embodiments are not intended to limit the present invention,but are intended to facilitate the understanding of the presentinvention. It is apparent that the present invention can be modified andimproved without departing from the gist thereof, and the equivalentsthereof are included in the present invention.

In the above embodiment, the lens holder 13 is formed with the fittinggroove 13 g extending in the upper-lower direction and the third portion93 c of the link 93 similarly extending in the upper-lower direction isinserted into the fitting groove 13 g. In this way, the tip end portion93 c 1 of the third portion 93 c serves as an acting point to which therotation action of the second screw 91 is applied. According to thisconfiguration, since, for example, the whole of the third portion 93 ccan be placed inside the right shaft portion 13 e, it is possible toconfigure the structure near the acting point in a relatively smallsize. Accordingly, the degree of freedom in designing a decorativemember or the like mounted to the lens holder is increased. However, therelationship between the groove and the acting point may be reversed.

FIG. 27 shows a lamp unit 10A according to a first modified example. Thesubstantially same or similar elements will be denoted by the samereference numerals as those of the lamp unit 10. The lamp unit 10Aincludes a lens unit 30A and a link 93A. The lens unit 30A includes alens holder 13A. The link 93A is formed with a fitting groove 93 dextending in the upper-lower direction. On the other hand, the lensholder 13A has a rod 13 h which is fitted to the fitting groove 93 d.That is, an acting point, to which the rotation action of the secondscrew 91 is applied, is a coupling portion of the rod 13 h and thefitting groove 93 d. The position of the acting point is located in aplane formed by the optical axis A and the reference axis B.

FIG. 28 shows a lamp unit 10B according to a second modified example.The substantially same or similar elements will be denoted by the samereference numerals as those of the lamp unit 10. The lamp unit 10Bincludes a lens unit 30B and a link 93B. The lens unit 30B includes alens holder 13B and a projection lens 14B.

FIG. 29 is a perspective view of an exploded state of the lens holder13B and the projection lens 14B, as seen from the rear. The lens holder13B has a lower end portion 13 i. The joint 53 of the leveling actuator15 is fixed to the lower end portion 13 i. That is, a front end portionof the joint 53 is not rotated relative to the lens holder 13B.

The lens holder 13B has a right slide groove 13 j and a left slidegroove 13 k. The right slide groove 13 j is formed at a portion of thelens holding portion 13 a and the right arm portion 13 c. The left slidegroove 13 k is formed at a portion of the lens holding portion 13 a andthe left arm portion 13 d.

The projection lens 14B has a right arm portion 14 a and a left armportion 14 b. The right arm portion 14 a extends rearward from the rightportion of the projection lens 14B. The right arm portion 14 a is formedwith a fitting groove 14 a 1. The left arm portion 14 b extends rearwardfrom the left portion of the projection lens 14B.

As the projection lens 14B is assembled from the front of the lensholder 13B, the right arm portion 14 a of the projection lens 14B isdisposed in the right slide groove 13 j of the lens holder 13B. At thistime, the fitting groove 14 a 1 formed in the right arm portion 14 a isdisposed in the fitting groove 13 g. Further, the left arm portion 14 bof the projection lens 14B is disposed in the left slide groove 13 k ofthe lens holder 13B. In this state, the right arm portion 14 a and theleft arm portion 14 b can be slid in the left-right direction within theright slide groove 13 j and the left slide groove 13 k, respectively.That is, the projection lens 14B is supported on the lens holder 13B tobe movable in the extension direction of the reference axis B.

FIG. 30 is a side view of the lamp unit 10B from which the lens unit 30Bis detached, as seen from the right. The link 93B has a fitting rod 93e. The fitting rod 93 e extends in an arc shape downward from the frontend portion of the second portion 93 b. An acting portion 93 e 1 whichis a portion of the fitting groove 93 e extends in the upper-lowerdirection. As shown in FIG. 29, the fitting groove 13 g included in thelens holder 13B also extends in an arc shape to match the shape of thefitting rod 93 e.

When the lens unit 30B is mounted as shown in FIG. 28, the fitting rod93 e of the link 93 is fitted into the fitting groove 13 g of the lensholder 13B and the fitting groove 14 a 1 of the projection lens 14B. Atthis time, the acting portion 9 e 31 is disposed at the same position asthe right shaft portion 13 e of the lens holder 13B with respect to theupper-lower direction.

FIG. 31 is a top view for explaining the movement of each part of thelamp unit 10B according to the rotation of the second screw 91. FIG. 31Ashows an initial state.

When the second screw 91 is rotated to the left from the above state,the first portion 93 a of the link 93 is pushed forward via the joint92. Consequently, the link 93 is rotated to the right with the fulcrummember 94 as a rotation axis, and the right arm portion 14 a of theprojection lens 14B is pushed to the right via the joint rod 93 e. Inthis way, the right arm portion 14 a and the left arm portion 14 b ofthe projection lens 14B are slid to the right in the right slide groove13 j and the left slide groove 13 k of the lens holder 13B,respectively. Further, the right shaft portion 13 e and the left shaftportion 13 f are moved to the right in the fitting grooves 31 b, 32 b ofthe right bearing 31 and the left bearing 32, respectively. Therefore,as shown in FIG. 31B, the optical axis A of the projection lens 14Bwhich is a portion of the lens unit 30B is translated to the right.

On the other hand, when the second screw 91 is rotated to the right, thefirst portion 93 a of the link 93 is pushed rearward via the joint 92.Consequently, the link 93 is rotated to the left with the fulcrum member94 as a rotation axis, and the right arm portion 13 c of the lens holder13 is pushed to the left via the third portion 93 c. In this way, theright arm portion 14 a and the left arm portion 14 b of the projectionlens 14B are slid to the left in the right slide groove 13 j and theleft slide groove 13 k of the lens holder 13B, respectively. Further,the right shaft portion 13 e and the left shaft portion 13 f are movedto the left in the fitting grooves 31 b, 32 b of the right bearing 31and the left bearing 32, respectively. Therefore, as shown in FIG. 31C,the optical axis A of the projection lens 14B which is a portion of thelens unit 30B is translated to the left.

That is, as the head portion 91 a of the second screw 91 is operated,the reference position in the left-right direction of the optical axis Aof the projection lens 14B is adjusted. A force of translating theoptical axis A acts on the projection lens 14B via the acting portion 93e 1 of the fitting rod 93 e. An acting point of the force is disposed ina plane formed by the optical axis A and the reference axis B.

According to this configuration, the projection lens 14B can be directlymoved in an extension direction of the reference axis B by the operationof the second screw 91. In this way, it is possible to suppress a momentof tilting the optical axis A in the left-right direction even when anacting point of the force to move the optical axis A is spaced apartfrom the reference axis B with respect to the direction of the opticalaxis A. Accordingly, it is possible to further improve the adjustmentaccuracy of the optical axis A while reducing the occupying space of thelamp unit 10B including a mechanism for adjusting the reference positionof the optical axis A.

In the above embodiment, the lamp units 10, 10A, 10B are assembled fromthe inside of the housing 2. However, the lamp units 10, 10A, 10B may beassembled from the outside of the housing 2, so long as the supporttable 11 b of the heat sink 11, which supports at least the light sourceunit 12, is disposed in the lamp chamber 3.

The light source 21 is not limited to a light emitting diode. Othersemiconductor light emitting element (an organic EL element, a laserdiode, etc.) or a lamp light source (an incandescent lamp, a halogenlamp, a discharge lamp, a neon lamp, etc.) may be used. Further, theshape of the reflector 23 can be any shape, so long as at least aportion of the light emitted from the light source 21 can pass throughthe projection lenses 14, 14B.

It is not necessarily required that the light distribution control unit16 is fixed to the support table 11 b of the heat sink 11 by the fixingmembers 64 a, 64 b. The light distribution control unit 16 can be fixedby a proper method, so long as the light source mounting portion 11 b 8is arranged to avoid the shortest path from the supported site to theportion of the heat sink 11 exposed to the outside.

It is not necessarily required that the operation control unit 17 isfixed to the control unit accommodating portion 11 e of the heat sink 11by the fixing member 64 c. The operation control unit 17 can be fixed bya proper method, so long as the light source mounting portion 11 b 8 isarranged to avoid the shortest path from the supported site to theportion of the heat sink 11 exposed to the outside.

It is not necessarily required that the first control circuit 71 a, thesecond control circuit 71 b and the third control circuit 71 c areprovided on the same board 71. These control circuits can be placed atproper sites of the lamp units 10, 10A, 10B, as necessary.

It is not necessarily required that the main surface of the board 71extends in the upper-lower direction. The direction of the main surfacecan be properly determined, depending on the specifications of the lampunits 10, 10A, 10B, so long as the main surface extends in a directionintersecting with the extension direction of the right table 11 b 1 andthe left table 11 b 2.

The rear ends of the right table 11 b 1 and the left table 11 b 2 arenot necessarily continuous. The cut-out 11 b 3 may reach the rear plate11 a, and the right table 11 b 1 and the left table 11 b 2 may becompletely spaced apart from each other.

In the above embodiment, the light source 21 is disposed on the upperside of the support table 11 b, and the leveling actuator 15 and theoperation control unit 17 are disposed on the lower side thereof.However, depending on the specifications of the lamp units 10, 10A, 10B,the leveling actuator 15 and the operation control unit 17 may bedisposed on the upper side of the support table 11 b, and the lightsource 21 may be disposed on the lower side thereof.

The direction of the optical axis A of the projection lenses 14, 14B,which are displaced by the leveling actuator 15, is not necessarily setto a direction corresponding to the upper-lower direction of a vehicle.For example, the direction may be set to a direction corresponding tothe left-right direction of the vehicle and the leveling actuator may beused as a swivel actuator.

In the case where it is not required to form a plurality of lightdistribution patterns by using a single light source 21, it is notrequired to provide the light distribution control unit 16 including themovable shade 61.

That is, the lighting device, on which the lamp units 10, 10A, 10Baccording to the present invention are mounted, is not limited to theheadlamp device 1. The present invention can be applied to a lampmounted to a suitable vehicle lighting device, so long as the lamp isutilized in an application where it is required to adjust the referenceposition of the optical axis A of the projection lenses 14, 14B.

This application is based on Japanese Patent Application No. 2013-173985filed on Aug. 23, 2013, Japanese Patent Application No. 2013-173986filed on Aug. 23, 2013, Japanese Patent Application No. 2013-173987filed on Aug. 23, 2013, and Japanese Patent Application No. 2013-173990filed on Aug. 23, 2013, the contents of which are incorporated herein byreference.

What is claimed is:
 1. A lamp to be mounted on a vehicle, the lampcomprising: a light source; a lens unit including a projection lenswhich is disposed such that at least a portion of light emitted from thelight source passes there through, and a holder which supports theprojection lens; and an adjustment mechanism configured to adjust areference position of an optical axis of the projection lens, whereinthe adjustment mechanism includes: a reference axis perpendicular to theoptical axis and disposed in a plane which intersects with a focal pointof the projection lens; a first screw configured to adjust the referenceposition in a first direction; a second screw configured to adjust thereference position in a second direction intersecting with the firstdirection; a first transmission mechanism configured to rotate the lensunit about the reference axis in accordance with rotation of the firstscrew; and a second transmission mechanism configured to move at least aportion of the lens unit in an extension direction of the reference axisin accordance with rotation of the second screw, and wherein an actingpoint of a force by the second transmission mechanism to move theoptical axis is disposed in a plane formed by the optical axis and thereference axis.
 2. The lamp according to claim 1, wherein the force bythe second transmission mechanism to move the optical axis acts on theholder.
 3. The lamp according to claim 1, wherein the projection lens issupported on the holder to be movable in the extension direction of thereference axis, and wherein the force by the second transmissionmechanism to move the optical axis acts on the projection lens.
 4. Thelamp according to claim 1, wherein the reference axis is formed on aportion of the holder.
 5. The lamp according to claim 1, wherein thefirst direction corresponds to an upwards and downwards direction withrespect to the front of the vehicle.
 6. The lamp according to claim 5,wherein the first transmission mechanism includes an actuator having adrive shaft for displacing the optical axis in the first direction, andwherein the first screw and the drive shaft are arranged along anextension direction thereof.
 7. The lamp according to claim 1, furthercomprising: a heat sink which supports the light source, wherein thefirst screw and the second screw extend through the heat sink.